1. Field of the Invention
The present invention relates to a paging system for transmitting numeric and alphanumeric pages and for recording voice messages.
2. Description of the Related Art
Paging systems are known and used to transmit pages on both a regional and national level. Each subscriber to a paging system is issued a pager having a unique pager identification number (PIN) and subscribes to selected services offered by the paging system.
Many conventional paging systems include a central computer for storing subscriber information, including PIN number, security code and types of services subscribed to. Pages called into these systems are processed by the central computer, sent to a transmitter and broadcast in the region corresponding to the subscriber's location. Transmission of the pages may be performed by satellite which allows subscribers to be paged anywhere in the country.
One such paging system is the National Satellite Paging System (NSP). As shown in FIG. 1, the NSP comprises a central computer 100, an alphanumeric speech unit 102, a voice mailbox unit 104 and channel banks 106. The central computer 100 comprises, for example, a MicroVAX computer available from Digital Equipment Corporation which, as described above, stores subscriber information and processes pages to be broadcast. This processing includes preparation of the pages into the proper protocol for transmission to a satellite (not shown) via satellite uplink 108 or to a local transmitter 110. In addition, the central computer 100 provides administrative and accounting functions, such as billing functions. The alphanumeric speech unit 102 is comprised of DECTALK interface units, also available from Digital Equipment Corporation, which provides voice prompting to a caller wishing to leave a page for a subscriber, in accordance with instructions from the central computer 100. The voice mailbox unit 104 comprises a BBL EVXTRA unit, available from BBL Industries, which provides voice prompting for a caller wishing to leave a recorded message for a subscriber. Channel banks 106 comprise intelligent T-1 channel banks available from Newbride Corp. and convert digital T-1 input lines into analog lines.
The NSP is capable of processing both numeric and alphanumeric pages and recording voice messages The numeric and alphanumeric page service provided by the NSP is termed the "SKYPAGER".RTM. service and the voice message service is termed the "SKYTALK".RTM. service. An example of each service and the corresponding system and processing will now be described.
If a caller wishes to page a subscriber with a numeric or alphanumeric page, the caller is connected with the NSP system by dialing 1-800-SKYPAGE. A numeric page generally refers to a message consisting only of numbers, such as a phone number at which the caller can be reached, and an alphanumeric page refers to any message including, but not limited to, numbers, letters, symbols and punctuation. The call comes into the alphanumeric speech unit 102 via a digital T1 line and channel bank 106. In response to the call, the alphanumeric speech unit 102 establishes a connection with the central computer 100 via one of several RS-232 ports. The central computer 100 instructs the alphanumeric speech unit 102 to welcome the caller to SKYPAGE and sequentially instructs the caller to enter the PIN of the subscriber and a numeric or alphanumeric message (usually a return phone number). The central computer 100 also reviews the subscriber's file (corresponding to the input PIN) to determine what type of services the subscriber is entitled to receive, processes the page into the appropriate protocol and transmits the page to the local transmitter 110 or a satellite uplink 108.
If a caller wishes to leave a voice message for a subscriber, he or she does so by dialing 1-800-SKYTALK. This call comes into the voice mailbox unit 104 via a digital T1 line and channel bank 106. In response to the call, the voice mailbox unit 104 sequentially instructs the caller to enter the PIN of the subscriber and a message. The message is recorded, for example on disk drives, at a storage area dedicated to the subscriber. Once the message is obtained and the caller disconnected, the voice mailbox unit 104 establishes communication with the central computer 100 using a Telocator Network Paging Protocol (TNpp, which is an open protocol for communications between paging terminals developed by Telocator) and informs the central computer 100 that the subscriber corresponding to the PIN entered by the caller has a message stored in the voice mailbox unit 104. The central computer 100 updates the subscriber's file with this information and transmits a page to the subscriber instructing the subscriber to call into SKYTALK and retrieve the message.
To retrieve a SKYTALK message, the subscriber dials 1-800-SKYTALK and, in response to voice prompts from the voice mailbox unit 104, inputs the appropriate information (PIN and function code) to effect play back of the message.
The NSP system is thus an efficient and comprehensive paging system offering its subscribers a wide range of services. However, the NSP system suffers from a number of disadvantages which limit its performance and unnecessarily elevate its costs. Specifically, as described above with respect to numeric and alphanumeric pages, the central computer 100 provides all of the page processing and administrative and accounting functions as well as the processing for SKYTALK and SKYPAGER transmission services. Expansion of the system is, therefore, very expensive since a larger central computer is required for expansion. Further, the central computer 100 can only process a limited number of calls at one time, which limits its ability to meet subscriber demands.
The NSP system is also limited in its functionality which tends to inconvenience subscribers While the NSP system does provide both SKYPAGER and SKYTALK services, a subscriber must use two different phone numbers to get these two different services. The system does not enable a subscriber to switch between these two services after an initial call into the system. For example, if a subscriber wishes to retrieve both numeric pages (which may be held for later retrieval) and voice messages, the subscriber must first call 1-800-SKYPAGE to retrieve the numeric pages then hang up and call 1-800-SKYTALK to retrieve the voice messages. This is both inconvenient and expensive.
Furthermore, the NSP system does not offer a subscriber the ability to dial out a phone number of a caller who has left a message and establish a phone connection via the NSP system to return the caller's message. For example, if a subscriber calls into SKYPAGER to retrieve numeric pages and desires to immediately return one of the phone calls, the subscriber must memorize or write down the phone number, assuming that the number is not already known, hang up the phone and dial the person directly. This, again, is both inconvenient and expensive.